An oxygen gas container has a volume of 20.0 L. How many grams of oxygen are in the container if the gas has a pressure of 876 mmHg at 23 C?

1 Answer
Jan 8, 2018

There are 30.430.4 grams of oxygen in the sample.

Explanation:

Use the ideal gas law. We are given the pressure, the temperature and the volume. The gas constant will be 62.3662.36

PV = nRTPV=nRT

We're looking for nn, the number of moles in the sample. Note that 23˚C= 23 + 273 = 296K

(20.0 L)(876 mmHg) = n(62.36 mmHg L k^-1 mol^-1)296K

If we cancel all units we're left with

n = 0.949 mol

Knowing that

"molar mass" = ("number of grams per sample")/("number of moles")

And that the molar mass of oxygen is 32.00 g/(mol), we can solve for number of grams in sample.

32.00 g/(mol) * 0.949 mol = g

g = 30.4 " grams"

Notice I rounded to 3 sig figs.

Hopefully this helps!